You could mix the Kaytee Clean and Cozy in with the current Oxbow bedding at first maybe and see how it goes, plus that means there will still be some familiar smelling substrate for the hamster so less stressful than changing it all in one go. I have no idea how much lol. Depends on the size of the bag I guess. Maybe get one of these and mix as much as you want in with current substrate this time, and get another whole bag for next time?
https://www.amazon.com/s/ref=nb_sb_n...Clean+and+Cozy